


High School Biology

by Strixes



Category: Supernatural
Genre: High School, Teen Dean Winchester, Teen Sam Winchester
Language: English
Status: Completed
Published: 2015-03-11
Updated: 2015-03-11
Packaged: 2018-03-17 10:11:27
Rating: General Audiences
Warnings: No Archive Warnings Apply
Chapters: 1
Words: 2,726
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/3525326
Author URL: https://archiveofourown.org/users/Strixes/pseuds/Strixes
Summary: <blockquote class="userstuff">
              <p>Dean got up and went to the bathroom. He closed the door and stared into the mirror. He looked at all the parts on his face that were mom. That left a lot of parts that weren't. He licked his lips. Mom didn't have lips like that. He ran a finger down the bridge of his nose. That wasn't mom's either. The freckles weren't mom's, neither were his eyes.</p><p>He leaned against the bathroom counter and tried to picture this mystery guy that was actually his dad.</p>
            </blockquote>





	High School Biology

**Author's Note:**

> This is somewhat spoilery for season ten. So I shall be vague about the explanation: In an episode this season Sam said that Dean's blood type was O. Way back in the early seasons we learned that John was blood type AB. The likelihood that a parent with type AB blood had a child with type O blood is slim but I doubt the show was implying that Dean isn't John's son. It's more likely a continuity error. Still, I like the idea that Dean is a cuckoo.

Dean didn't know what the hell he had been thinking— no scratch that, he had been thinking that Jen Brookfield was hot and was _at least_ a D-cup. He had followed that pair of personalities right into their science class. Now he was stuck listening to the teacher go on about some guy named Reggie P. Either the guy's parents had hated him or the teacher was lame and thought calling some old dead science dude Reggie P was going to make people sit up and listen.

It made Jen Brookfield sit up and listen. Even lean forward a little. A lot actually. And that shirt was cut freakin' _low._

"Dean, right?"

Dean snapped his head around. The teacher was staring at him. Dean tried not to squirm in his seat. He flicked the corner of his notebook. "Yeah."

"Why don't you come fill in one of the Punnett squares?" The teacher asked.

Dean let out a long suffering sigh and rolled his eyes. Why did teachers _ask_ when what they really meant was, _get up here and do it because I said so_. He pushed up from his desk, "Sure."

The teacher - Dean hadn't bothered to learn his name, they'd be gone in a couple weeks - picked a few other students to fill in squares. That was a stroke of luck because Dean had no freakin' clue how to fill in one of the grids on the chalkboard. Reggie P 's life work was boring as hell. Dean had glazed over when the teacher started talking about pea plants. Who freakin' cared about pea plants?

Dean took his time picking out a piece of chalk from the ledge and rolled it around in his hands while the other kids started filling in the grids. Dean watched for a moment before he caught on; write the letter on top down each column and right the letter on the side across each row. He shook his head. This was supposed to be science? Writing letters in boxes?

He was skipping tomorrow. This was stupid. He fought monsters. He saved people. He didn't need to sit in a classroom and write letters in boxes to do that. Actually he couldn't think of anyone who needed to sit in a classroom and do that. This was useless.

He read the letters on top, A and B and the letters on the side O and O then scrawled the letters into the boxes. He tossed the chalk back on the ledge and sat back down.

The teacher went over the examples with the class. He pointed to the first grid on the blackboard, "You can see if both pea plants only have G genes, you'll only get green peas even though they're all recessive because there are no dominant Y genes to make yellow peas."

More pea plants. Great.

The teacher moved on to the next grid, "Now here we have Xs and Y. XX is all the ladies in the classroom XY is all the gentlemen. Even though there are three possible Xs in the square there is still a fifty percent chance that a baby will be a boy because the Y gene is still paired up half the time."

No freakin' shit. Dean could have told him that without a grid. Whether a kid was going to be a boy or a girl was like flipping a coin. There was only two sides to the coin so of freakin' course it was 50/50 odds. Jesus, he had been playing more complicated odds in bars with fake ID since he was 15. A bar was a better classroom than this. He let out a long bored sigh.

Jen Brookfield shot him a dirty look. He smiled over at her and turned his charm up to eleven. She made a pouty annoyed face then sighed and smiled. Dean grabbed his pencil and scribbled a note in his notebook. He slid it over towards her, _What're you doing after school?_

She grabbed her pen. He watched her hand loop over the page. She was one of those girls that had bubbly hand writing. She pushed the notebook back to him.

Dean read it over, _Gymnastics club. But we could meet up after._

Dean grabbed his pencil and started writing. He had already scoped out the local scene. He had a good idea of where to take a girl and show her a good time.

"Dean. It's good to see you're taking notes."

Dean looked up. The teacher was staring at him.

"Uhh...yeah. Love me some biology." Dean said. He started drawing a grid and filled it out with the same one he had done on the board.

"That's good to hear. Now the Punnett square you filled out is for blood types." The teacher said. "We have a parent with AB blood here." The teacher pointed to the top. "And a parent with O blood here. As you can see their children have neither O or AB blood. They'll have either A blood or B blood and be carriers for the recessive O gene."

Dean nodded and went back to passing notes to Jen Brookfield. Gymnastics club was giving him all kinds of—

He looked back at the grid in his notebook. He looked at the grid he had filled out on the chalkboard as if it had changed while he wasn't looking. His lip twitched.

The rest of the class dragged on. The bell rang. He shoved out of his seat and headed for his locker. Jen Brookfield stopped him in the hall and asked him if he was going to wait for her gymnastics club to finish their meet. He told her he had to go pick up Sam.

"Oh...okay then." She looked down the hall as the other kids moved around them. "...want to walk me to my history class?"

"I, uh, got some stuff to do." Dean said. He didn't wait for her to ask what kind of stuff he had to do in the middle of the school day.

He found his locker as the halls emptied out and dug out the science textbook he had been given at the beginning of the week. He hadn't even opened it yet. He tucked it under his arm and closed his locker and slipped out a side door and headed for the park.

The whole walk over that textbook felt like a lead weight. He found an out of the way bench and sat down. He flicked the book open to the back and looked through the index for a Reggie P.

He didn't find it of course because his teacher was a tool and hadn't even been using the dead guy's full name. He flipped through the book at random for a few moments before going back to the index and looking up blood types.

He flipped to page 381 and started to read. His eyebrows pulled down. The more he read the further his eyebrows moved down. He had a headache from frowning by the time he was done reading.

A and B were dominant blood types but they could do this thing and be co-dominant and that was how people got AB blood; at least that was what he thought the textbook was saying.

Dad was AB. He knew because he had played with dad's dog tags when he was little and because he couldn't count the number of times dad had landed in the hospital after a hunt and needed blood. Dad was AB for sure. The army and every hospital they had ever been in couldn't have made a mistake like that because dad would have keeled over long ago if they had been messing up his blood type for years.

He opened up his notebook and looked at the grid he had already drawn. He didn't know what mom's blood type was but it had to either be A or B and carry O or it had to be O. He drew two more grids. He already had the AB and OO blood type grid.

He drew the AO and AB grid first. That got him two A blood types, one B blood type, and one AB blood type. Sam had type A blood. The textbook had said that was common. A lot of people had type A blood and if mom had type A blood and dad had type AB it made a lot of sense that Sam had type A blood too.

He did the grid for BO and AB. There was more type B blood. B was supposed to be rare, like type AB.

None of the grids on the paper had anyone being type O because according to the textbook type O was recessive so if there was an A or a B involved that person got type A or B blood instead of type O.

He was type O.

He drew another grid just to prove to himself what he already knew.

He labeled the top part OO and the side OO and filled in the squares inside with more Os.

Great big fat Os.

He looked back up at the AB on that first grid. His face turned red. He scribbled the page out and tossed the notebook away. He slammed his textbook shut and shoved off the bench. He stomped away, mad at someone and something but he wasn't sure who or what.

Type freakin' O.

He spent the rest of the day bumming around town until he had to pick up Sam. Sam nattered on about how great school was. He nodded here and there and let it go in one ear and out the other.

Mom must have been type O.

...what if mom _wasn't_ type O.

Who the fuck were his parents?

"You alright?" Sam asked.

"Yeah." Dean said. Except he was either adopted or some other guy's kid.

"You're doing homework?" Sam asked curiously.

"Huh?" Dean looked down at him confused.

Sam pointed at the textbook under his arm.

Dean looked down at it. He glared at the book. Fuck the textbook. He tossed it onto some yuppie's front lawn. "Nope."

"Dean!" Sam darted over and grabbed the textbook. He brushed the cover off. He gave Dean a dirty look and didn't give the textbook back.

Dean rolled his eyes. Count on Sam to protect a freakin' textbook.

They walked back in silence, Sam occasionally letting out whiny noises and disapproving sniffs over the textbook still. Dean ignored him because he had more important things on his mind than a ratty old textbook from a school they were going to ditch in a couple of weeks.

What the hell did he say when dad showed up?

Hey **_John_** _,_ ever gonna tell me who my parents are?

Freakin' hell. He couldn't say that. He pursed his lips together and pulled up the collar of his jacket and tried to disappear. He couldn't see dad as the adopting type. Mom was probably still his mom. But he knew mom and dad had been married _before_ he was born so he couldn't have been mom's kid from some other relationship. Mom must have been cheating.

Dean stopped on the sidewalk and stared blankly ahead. He had always thought that all that fighting mom and dad had done was over dad's drinking. That mom had been the one to put up with dad. But what if dad had been drinking because he knew mom had been cheating? What if dad had moved out for those couple days because he found out what mom was doing?

"Dean?"

Dean shook his head and looked down at Sam, "What?"

"You sure you're alright?" Sam asked.

"Yeah." Dean said.

"...then why are we just standing here?" Sam asked.

Dean strode forward, "We're not. Come on."

Sam started going on about some history test he was _excited_ about. Dean nodded his head and grunted in acknowledgement from time to time. All he had wanted to do today was try and persuade Jen Brookfield into a movie theatre or some crap and make out with her, maybe get a chance to feel those D-cups. Now he was trying to figure out who the fuck his dad was.

He couldn't remember mom going out at strange hours or another man coming around. Actually when he thought about it he couldn't remember anyone coming to the house. His parent's - the people who he thought were his parents - didn't seem to really have any friends even before dad started dragging them across the country looking for what killed mom.

Who had mom been seeing? He almost stopped short again. Jesus Christ. Was he the milkman's kid? ...did Lawrence even still have milkmen then? He screwed up his face trying to figure it out. He was almost sure that milkmen were some weird 50's thing. So he probably wasn't the milkman's kid.

They made it back to the motel without him snapping at Sam that he didn't care about a history test because he didn't know who the hell his dad was.

He got dinner ready for Sam and made sure they didn't have to do an emergency laundry run for tomorrow then he dropped down on his bed and flicked the tv on for noise while Sam did his homework.

He didn't actually watch tv. He just needed something to stare at so Sam wouldn't bug him. His eyes flicked over to Sam‒ his **_half_** brother. Things slowly clicked into place. The way dad was always telling him to look out for Sam, watch Sam, protect Sam. Sam. Sam. Sam. As if he wouldn't watch over his little brother‒ half brother. No wonder dad thought he'd screw up. He was what happened when two people screwed up a marriage and Sam was all dad really had left of mom.

Unless Sam wasn't dad's kid either.

He flicked his eyes back to Sam and snorted. Fat chance in hell that Sam _wasn't_ dad's kid. Those two were so alike Dean was always worried they'd start going for each other's throats. Sam even looked like dad.

He didn't look like dad. He didn't even really look like Sam all that much.

He got up and went to the bathroom. He closed the door and stared into the mirror. He looked at all the parts on his face that were mom. That left a lot of parts that weren't. He licked his lips. Mom didn't have lips like that. He ran a finger down the bridge of his nose. That wasn't mom's either. The freckles weren't mom's, neither were his eyes.

He leaned against the bathroom counter and tried to picture who this mystery guy had been. Some neighbour with green eyes and freckles? Some guy she met grocery shopping with a sharp nose and thick lips? Had he been—

**_Was he alive?_ **

Did he have some whole other family out there that he didn't know about? Brothers and sisters he had never met? **_Half_** brothers and sisters he had never met. Grandparents that were still alive? Did he have a dad that wasn't dragging his kids all over the damn country living out of motels and a car? If he tracked this guy down and showed up one day out of the blue would he have a _home?_

He shoved away from the bathroom counter. He had a home. It was with Sam. He flung the bathroom door open and stomped back to the bed. He threw himself down and angrily stared at the tv.

So what if John treated him differently from Sam. He couldn't blame the guy, he was raising some other dude's kid. At least John had kept him when mom died. He could have found his real dad and just dumped him off with him and he'd never have seen Sammy again.

And he was still mom's kid and Sam was mom's kid. They were brothers. He had a brother even if mom was dead and he didn't know his real dad and John wasn't even around half the time to pretend to be his dad.

He didn't need some asshole he had never met with type freakin' O blood trying to pretend to be his family. Sam was his family.

Fuck Reggie P and his pea plants.

**Author's Note:**

> Dean's understanding of punnett squares and blood types isn't the best. There are other ways to end up having type O blood instead of having two type O parents. There are in fact scenarios where a parent with type AB blood can indeed have a child with type O blood but Dean doesn't know that. It's rather rare anyway.


End file.
